// //在浏览器控制台中记录hello world
// let a = 10;
// a = 100;
// const b =  20;
// //b = 10;不能修改b
// const filepath = "./wwwroot";
// const rate = 2.5; //与a类型相同都是number
// const is_true = true;
// const z = null; //此时的z被定义了，但是这是
// const j = undefined;
// //let s; //与j类型相同都是未被定义

// const username = "claus";
// const age = "20";
// username.tolow
// //console.log(typeof s);
// console.log("My name is " + username + ",i am " + age);
// console.log(`My name is ${username},i am ${age}`);
// const wort = `My name is ${username},i am ${age}`;
// console.log(wort);

// const s = "hello world";
// // console.log(s.length);
// // console.log(s.toUpperCase());
// const s1 = "HELLO,WORLD";
// //console.log(s1.toLowerCase());
// let pos =s1.indexOf(",");
// const s2 = "苹果,香蕉,菠萝,凤梨";
// console.log(s1.substring(0,pos)); //HELLO
// console.log(s2.split(","));

// let numbers = new Array(1,2,3,4,"claus");
// let numbers = [1,2,3,5,"claus",true,null,undefined];
// numbers.push("log.txt");
// numbers.unshift("hello");
// numbers.shift();
// let pos = numbers.indexOf("claus");
// console.log(Array.isArray(pos));

// let person={
//   pname:"claus",
//   age:18,
//   sex:"男",
//   hobbies:["fitness","basketball","football"],
//   address:{
//     nationalty:"china",
//     city: "CQ",
//     street:"west road 0151",
//   },
// };
// person.email = "3266928143@qq.com"
// const {pname , age ,address} = person;

// console.log(person.email);

// const task = [
//     {
//         id:1,
//         message:"Go to the Shop",
//         iscreate: false,
//     },
//     {
//         id:2,
//         message:"go to the shool",
//         iscreate: false,
//     }
// ]

// console.log(task[1].message);
// const jasonS = JSON.stringify(task);
// console.log(jasonS);
// const a = "10";
// if(a === 10){
//     console.log("a is 10");
// }else{
//     console.log("a is not number 10")
// }

const a = "10" ;

const color = a ==10 ? "grep" : "blue";

// console.log(color);

switch(color){
    case "blue":
        console.log("color is blue");
        break;
    case "read":
        console.log("color is read");
        break;
    default:
        console.log("color is undefined");

}